Portable fan



FIG. 1 is a right side front perspective view of a portable fan showing my new design;

FIG. 2 is a left side rear perspective view thereof;

FIG. 3 is a front elevation view thereof;

FIG. 4 is a right side elevation view thereof;

FIG. 5 is a left side elevation view thereof;

FIG. 6 is a rear elevation view thereof; and,

FIG. 7 is a top plan view thereof.

The broken line showing of a front grill, right side controls, right side grill, and left side grill are included for the purpose of illustrating environmental structure and forms no part of the claimed design. 

CLAIM The ornamental design for a portable fan, as shown and described. 